Horizontal Mattress Suture Technique on Microvascular Anastomosis of rat (body weight: 200-250 gm) femoral artery was evaluated. The present study was conducted to compare the horizontal mattress suture with simple interrupted suture on the suture time, patency rate of the sutured vessels, and the histological changes of surgical site of the vessel wall during wound healing period. The mean suture time of the vessel wall with horizontal mattress suture technique was 15 min 49 sec ± 2.14, which is significantly shorter than that of simple interrupted suture technique. The patency rate of the sutured vessel in both groups was statistically not different each other till post-operative 3rd day but patency rate of horizontal mattress suture was higher than that of simple interrupted suture at post-operative 3rd week. The histological findings such as intimal noss, medial degeneration and intimal regeneration were similar in both groups.